Julian P. Boom and Fleur Pierets say they plan to get married in every country that recognizes same-sex marriage. Since September, the lesbian couple has exchanged vows in the United States, the Netherlands, Belgium and France. By 2019, they plan to wed at least 20 more times.

For them, the global challenge is both activism and performance art. Its aim is to celebrate matrimony at a time when discrimination is still prevalent against lesbian, gay, bisexual and transgender individuals.

"We figured that marriage and love -- something that everyone can relate to -- is a perfect starting point to raise awareness," Booms said.

22 countries and counting

Boom and Pierets fell in love seven years ago in Amsterdam and began collaborating artistically. They split their time between Antwerp, Belgium and Amsterdam. Known jointly as JF Pierets, the duo founded Et Alors? Magazine, a platform that explores mainstream understanding of identity, gay imagery and female representation in art. A recent edition, titled Genderblender, featured more than 20 different artists' representations of gender identity through painting, photography, and performances.

"All our work is trying to capture current times and how the world functions on the level of gay and gender equality. ... How it is changing and evolving," Pierets said.

Their work developed into the marriage project titled "22," the number of countries with marriage equality when they conceived the project. Since then, two more countries have legalized same-sex marriage -- Malta in July and Germany in October. Those countries have been added to the itinerary, but the name remains "22."

Australia will likely be added to their travel plans. Prime Minister Malcolm Turnbull said the legalization of same-sex marriage could happen there by Christmas.

Austria is also due to join the list after the nation's top court ruled this week that same-sex couples can get married starting in 2019.

"As long as we're working on the project, we'll add every country that legalizes same-sex marriage," said Boom. "Fingers crossed for Australia, Taiwan and Chile."

It's progress. But there's still a long way to go.

"At the current rate, we will reach global recognition of same-sex marriage in the year 2142. That's 125 years from now," Pierets said.

Same-sex marriage is often regarded as a litmus test for LGBT equality, an important step in fighting discrimination against LGBT families. However, marriage laws and LGBT rights vary dramatically across the globe.

Twenty-four countries have legalized same-sex marriage since the first gay couple legally wed in the Netherlands in 2001. The United States, Canada and most Western European countries recognize same-sex marriage while most African countries do not. Same-sex marriage is illegal across Asia. That's poised to change after Taiwan's Constitutional Court ruled the current law unconstitutional and gave Parliament two years to change or enact new laws.

Documenting an evolution

Boom and Pierets aim to complete the project by summer 2019. While not every wedding will be legally binding, they will be officiated by certified civil servants in formal locations.

They plan to showcase their travels in New York, the host city for the 2019 World Pride parade, with a film and photo exhibition.

Already, the project is drawing accolades and support from advocacy groups.

"This project is a powerful and moving demonstration of the importance of equal marriage not only in Europe but across the world," said Steve Taylor, communications director of ILGA-Europe, an international nongovernmental organization advocating for human rights and equality for LGBT people at the European Union. "Love should never be illegal."

The couple hopes that the project will document the evolution of same-sex marriage and signify the possibility of change.

"This project is about sharing with people what you feel and experience, but always in style and in a positive way," said Pierets. "In our opinion, that's the first step towards lasting change."